I have a 2004 (i Think) Yamaha Beartracker 250 ATV 2WD. It has sat up for about a year and i went to ride it again only to find out the battery has gone dead and the carburetor is gummed up. I tore it apart and cleaned it only for it to run wide open but the butterfly valve for the throttle is closed. I brought the atv to a professional dragster mechanic up the street from me and he tried to figure out the problem by tuning it. No matter what he tuned on it, it would always run wide open. I bought a brand new carburetor ($600) and it still has the same issue. What could be the problem? Could the carburetor be fine and something else is wrong?